A silver halide photographic material generally comprises a support such as a plastic film, paper or a paper coated with polyethylene having coated thereon a silver halide emulsion layer and, if necessary, various combinations of constituting layers such as an interlayer, a protective layer, a backing layer, an antihalation layer and an antistatic layer.
The silver halide photographic material generally comprises a hydrophilic colloid layer such as gelatin as a binder on at least one side of the support. The hydrophilic colloid layer has a defect since it is liable to be expanded and contracted by the change of humidity or temperature.
Variation in the dimension of the photographic material caused by expansion and contraction of the hydrophilic layers is an important defect of the photographic material for printing which requires reproduction of dot images and precise line images for the multi-color print.
In order to obtain a photographic material having less variation in the dimension, i.e., having an excellent dimensional stability, a technique for regulating a thickness ratio of the hydrophilic colloid layers and the support is disclosed in U.S. Pat. No. 3,201,250, and a technique for incorporating a polymer latex into the hydrophilic colloid layers is disclosed in JP-B-39-4272, JP-B-39-17702, JP-B-43-13482 and JP-B-45-5331 (the term "JP-B" as used herein means an examined Japanese patent publication), and U.S. Pat. Nos. 2,376,005, 2,763,625, 2,772,166, 2,852,386, 2,853,457, 3,397,988, 3,411,911 and 3,411,912. Also, the theoretical background of the above-described techniques is described in J. Q. Umberger, Photo. Sci. and Eng. (1957) pages 69-73.
Further, a technique for coating a polyester film support with a vinylidene chloride copolymer is disclosed in U.S. Pat. Nos. 4,645,731, 4,933,267 and 4,954,430. Furthermore, a technique using a low humidity drying and a heat-treatment is disclosed in JP-A-1-229240 and JP-A-1-229244 (the term "JP-A" as used herein means an unexamined published Japanese patent application).
However, in recent years, high precision printing have been used more and more, and a further improvement in the dimensional stability of the photographic material is strongly desired. Generally, polyester type polymers, typically, polyester terephthalate (hereinafter referred to as "PET") are used as plastic supports of the silver halide photographic materials used for the photomechanical process. PET films have excellent characteristics in dimensional stability, mechanical strength and producibility and hence have been widely used.
However, even when the conventional technique for improving the dimensional stability is used, the PET film still does not sufficiently fulfil the requirements for the precision printing.
Films of styrene type polymer having a syndiotactic structure with a low coefficient of moisture swelling (hereinafter referred to as "SPS") as compared with the polyester film is disclosed in JP-A-3-131843. The silver halide photographic material for the photomechanical process using the SPS film as a support has an improved register of a plurality of plates in the multi-color print, but is still insufficient for the high precision printing.
Poor register in the photomechanical process is caused by various complicated factors such as variation in the dimension by temperature and moisture, optical characteristics and contact during light-exposure, and variation in the dimension by development processing.
Accordingly, development of a silver halide photographic material which makes the register easy has been strongly desired.